# SignGate Agent Buyer Identity Preflight – x402 Purchase Governance

> SignGate Agent Buyer Identity Preflight – x402 Purchase Governance is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Evaluates whether an AI agent's buyer identity, role, and risk profile are authorized to purchase a specific x402-gated API, dataset, or tool before the payment is made.

## Facts

- Endpoint: GET https://base-agent-preflight.bytoken2023.workers.dev/v1/x402/agent-risk/policy-decide
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signgate-agent-buyer-identity-preflight-x402-purchase-governance-01133ef9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Gy2bjru3SnNNjpEO_FrPz

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability signgate-agent-buyer-identity-preflight-x402-purchase-governance-01133ef9
```

Example prompt: Before you pay for that x402 API access, run a preflight check — request ID 'req-abc123', action 'api.purchase', risk score 20, amount 5.00 USDC — and tell me if our agent is cleared to buy it.

## When to prefer this

Use this endpoint when an AI agent is about to autonomously spend USDC via the x402 protocol and you need a policy gate to confirm the buyer role, transaction amount, and risk level are within approved parameters before funds are committed. Prefer this over post-hoc auditing or no governance at all when operating agentic wallets with real financial exposure. Especially valuable for multi-agent systems where different agents have different spending authorities.

## Known failure modes

- Missing required query params (request_id or action) returns a 400 or schema validation error
- Invalid pattern for request_id or action (non-alphanumeric characters) causes rejection
- risk_score value outside 0-999 integer range may fail pattern validation
- Service unavailable on the Cloudflare Worker edge returns a 5xx error
- High risk_score or flagged identity returns an assessment blocking the purchase without an error code
- Ambiguous or unknown action string may result in a default-deny policy decision

## How this service works

Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.

## Output

Returns a JSON object containing the network (e.g. eip155:8453), product identifier, and an assessment object with a risk_level (e.g. 'low', 'medium', 'high'), a numeric risk_score, and any policy flags raised. A clean response with no flags and 'low' risk_level means the agent is cleared to proceed with the purchase.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "request_id",
      "action"
     ],
     "properties": {
      "action": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_.:-]{2,80}$"
      },
      "request_id": {
       "type": "string",
       "pattern": "^[A-Za-z0-9._:-]{1,128}$"
      },
      "risk_score": {
       "type": "string",
       "pattern": "^[0-9]{1,3}$"
      },
      "amount_usdc": {
       "type": "string",
       "pattern": "^[0-9]+(?:\\.[0-9]{1,6})?$"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "network": {
       "type": "string"
      },
      "product": {
       "type": "string"
      },
      "activity": {
       "type": "object"
      },
      "identity": {
       "type": "object"
      },
      "assessment": {
       "type": "object"
      },
      "provenance": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "network": "eip155:8453",
  "product": "policy-decide",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signgate-agent-buyer-identity-preflight-x402-purchase-governance-01133ef9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-agent-preflight.bytoken2023.workers.dev](https://www.zero.xyz/host/base-agent-preflight.bytoken2023.workers.dev/llms.txt)